regina::PacketData< Held >::ChangeEventSpan Class Reference

An object that facilitates firing packetToBeChanged() and packetWasChanged() events. More...

#include <packet/packet.h>

Public Member Functions
	ChangeEventSpan (PacketData &data)
	Creates a new change event object for the given Held data. More...
	~ChangeEventSpan ()
	Destroys this change event object. More...
	ChangeEventSpan (const ChangeEventSpan &)=delete
ChangeEventSpan &	operator= (const ChangeEventSpan &)=delete

Detailed Description

template<typename Held>
class regina::PacketData< Held >::ChangeEventSpan

An object that facilitates firing packetToBeChanged() and packetWasChanged() events.

This performs the same function as Packet::ChangeEventSpan; see that class for full details on how it works. The main differences are:

• If the underlying Held object is not actually part of a larger PacketOf<Held>, then this ChangeEventSpan will do nothing. In such a scenario, the ChangeEventSpan constructor and destructor are both extremely cheap (each will make just a single integer comparison).
• If the underlying Held object is part of a PacketOf<Held>, then this ChangeEventSpan will ensure that the appropriate packet events are fired (just like Packet::ChangeEventSpan).

Just like Packet::ChangeEventSpan, these objects can be nested so that only the outermost object will fire change events; furthermore, PacketData<Held>::ChangeEventSpan objects and Packet::ChangeEventSpan objects can be nested within each other.

When working with PacketData<Triangulation<3>>, this class includes special code that nullifies a SnapPea triangulation when its inherited Triangulation<3> data changes unexpectedly. See the SnapPeaTriangulation class for details.

ChangeEventSpan objects are not copyable, movable or swappable. In particular, Regina does not offer any way for a ChangeEventSpan to transfer its duty (i.e., firing events upon destruction) to another object.

Constructor & Destructor Documentation

ChangeEventSpan()

template<typename Held >

regina::PacketData< Held >::ChangeEventSpan::ChangeEventSpan ( PacketData &  data )

inline

Creates a new change event object for the given Held data.

If data is part of a PacketOf<Held>, and this is the only ChangeEventSpan currently in existence for data, then this constructor will call PacketListener::packetToBeChanged() for all registered listeners for the packet.

Parameters

data	the object whose data is about to change; this may or may not be of the subclass PacketOf<Held>.

~ChangeEventSpan()

template<typename Held >

regina::PacketData< Held >::ChangeEventSpan::~ChangeEventSpan

inline

Destroys this change event object.

If the underlying Held object is part of a PacketOf<Held>, and this is the only ChangeEventSpan currently in existence for it, then this destructor will call PacketListener::packetWasChanged() for all registered listeners for the packet.

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The documentation for this class was generated from the following file:

• packet/packet.h